DESCRIPTION (Taken from the Investigator's Abstract) This proposal will allow the candidate to gain knowledge and skills in environmental epidemiology under the direct supervision of a highly qualified sponsor, further enhancing his potential to develop into an independent investigator. The candidate is trained in pediatrics and medical toxicology, and he is presently studying for a Masters in Public Health degree in Quantitative Methods. In addition, he has spent the past two years at the Channing Laboratory working directly with the Metals Epidemiology Research Group. This collaboration has already resulted in the publication of two research papers on the relationship of iron stores to lead poisoning, which is a primary focus of this proposal. The first two years of this proposal will incorporate needed course work, seminars and experience in statistical analysis, molecular epidemiology and assessment of neurocognitive function. This will enable the Dr. Wright to undertake an intensive research experience in the latter three years of the proposal. The long-term goal of the candidate is to develop into an independent investigator in the field of environmental epidemiology, with specific expertise in neurodevelopmental assessment and molecular epidemiology. This proposal outlines his career development plan, which includes work with established experts in environmental health, neuro-epidemiology, neuro- radiology, statistics, medical toxicology and population genetics. His development as a researcher will be enhanced both by course work at the Harvard School of Public Health and by directly working with the research team on projects involving neurotoxicology and molecular epidemiology. The overall scientific goal of this study is two-fold: 1) to determine whether elevated bone lead concentrations are associated with neurochemical changes in the frontal lobes and hippocampus of human subjects, and 2) to determine whether hemochromatosis genotypes are associated with increased bone lead concentrations. This proposal will take advantage not only of the intellectual and laboratory resources described herein, but also the data and archived samples from the long-running, longitudinal Normative Aging Study (NAS) that form the basis of the sponsor's "Lead RO1" (ES 05257-08 Lead Biomarkers, Aging and Chronic Disease).